Couple watches Vic wedding venue burn

A Sydney couple watched on as their wedding venue went up in flames in Victoria.

Fire engulfed waterfront restaurant The Baths in Sorrento, on Victoria's Mornington Peninsula, on Sunday night.

Fire crews found the building fully alight and it took about 40 firefighters to bring the blaze under control, which completely destroyed the restaurant.

A wedding photographer says a Sydney couple were due to marry at the venue on Friday.

"They were staying just a few hundred metres up the street and someone contacted them and let them know and they went down and actually watched the fire," he told 3AW.

The Baths owner James Gibson said the restaurant would help couples find alternative arrangements for weddings.

"We are devastated that The Baths restaurant has burnt down. Thankfully no customers or staff have been injured," Mr Gibson said on Facebook.

The restaurant was closed at the time and an investigation into the cause of the fire is being conducted.